A study of the value of offensive rebounds

There are a lot of statistics regarding the performance of NBA players and teams, many of which we have to take at face value for lack of a better understanding of their importance. One area in this regard is offensive rebounds -- to some they are simply a retention of possession (a low percentage "pass" if you will) while to others they command great respect, in some statistical rating systems being credited as worth more than three points per!

In trying to establish what impact offensive rebounds truly have, we'll query our database for some facts on what's happening on the offensive glass in the NBA 2003-04 season so far.

1) General Offensive Rebounding Percentages
First off, teams this season get an offensive rebound on about 29% of missed shots, although breaking it down a little further we find the following:

Shot Type

Off. Reb%

Jumper

28.5%

Close Up

34.4%

Dunks

29.6%

Free Throws

13.9%

So "Close" shots stand a somewhat better chance of being grabbed by an offensive player in the event of a miss (yet another reason why teams that shoot from near the basket do better), while missed free throws are tough to get second chances on.

2) Offensive Rebounding Percentages by Shot Clock timing
Another consideration is that perhaps the time left on the shot clock has some influence over the likelihood of an offensive rebound. We will exclude rebound situations off free throw misses, since the shot clock was not on in that circumstance.

Seconds Used

Off. Reb%

0-10

33.6%

11-15

27.0%

16-20

27.7%

21+

30.2%

Surprisingly there is some difference in when a shot is taken on the shot clock and the likelihood of an offensive rebound -- quickly taken shots stand the best chance of the shooting team recovering a miss.

We can account for the variance perhaps as a result of transition shots in the 0-10 second range where not all players are back and there's a greater chance presumably that the shot is from close range. At the end of the shot clock cycle there's also a slight nudge up in percentage, which we would hypothesize comes from the defense being so focused on defending/preventing the under pressure shot that they sacrifice a little in rebound positioning.

3) Shooting Percentage after an Offensive Rebound
When a team does grab an "O Reb" what is the expected value of the next shot? It makes sense to break this down two ways: when the offensive rebounder goes right back up with a follow-up shot, and when the ball is essentially kicked back out and the team restarts the offense. We'll also compare these numbers to the percentages on the first shot of a possession.

Shot

FG%

eFG%

Right Back

50.4%

50.9%

Restart

42.2%

47.0%

First Shot

43.2%

46.5%

It's clear then that when a team gets an offensive rebound and follows up with a shot right away by the offensive rebounder, the expected outcome is much better than for the first shot taken on a possession.

There are a few immediate follow-up three-pointers happening off an offensive rebound, but for the most part the shots are from close to medium range. On the other hand, when the offense is restarted after an offensive board, or at least the ball is passed out by the offensive rebounder, there's a high number of three-point shots taken, which hurts the overall FG% number, but shows a slightly improved effective Field Goal percentage (adjusted for the 3's made). We suspect that what may be occurring is that with the offensive rebound, the defense collapses towards the hoop, leaving the perimeter players with tempting looks from long range, should they receive the kick out pass.

However, what we're seeing essentially is that an offensive rebound with a quick follow on shot is a strong situation for the offense, whereas an offensive rebound that is then passed back out leads to an expectation that's roughly equivalent to a brand new possession.

4) "Right Back" Shots by Type
Perhaps the real advantage on the shot following an offensive rebound is that the rebounder has secured a good position near to the hoop?

Shot Type

Att.

FG%

Jump

20%

35.7%

Close

45%

51.3%

Dunks

8%

87.7%

Tips

27%

49.0%

As we suspected, the vast majority of quick shots after an offensive rebound are from close range, dunks or tips, and that accounts in part for the high overall field goal percentage on these putbacks. The defense is also likely to be off-balance.

On those occasions when the offensive rebounder is some distance from the hoop, the player is generally better off passing than taking the jumper! It may seem like the shot is there having secured the rebound, or perhaps the mindset, ingrained after years of playing, has been to go right back up with the ball, but judgement is clearly needed as a 35% field goal percentage result seems like a shame after earning your team a second chance.

5) Top Offensive Rebounding Scorers!
Theory is certainly the foundation of our intent -- ultimately to understand better what makes for a winning NBA team. However, it's always nice to spice up the dry stats with a few player specific numbers, so we'll take a brief intermission and look at which guys need to be respected for their offensive glass-cleaning and basket-stuffing prowess.

Rank

Player

Team

FG

FGA

FG%

Pts

1

Randolph

POR

44

75

59%

88

2

Dampier

GSW

37

74

50%

74

3

O'Neal

IND

37

60

62%

74

4

Ilgauskas

CLE

32

54

59%

64

5

Kirilenko

UTA

32

48

67%

64

6

Jamison

DAL

31

58

53%

62

7

Nesterovic

SAS

30

59

51%

60

8

Richardson

LAC

28

44

64%

59

9

Grant

MIA

29

51

57%

58

10

Thomas

PHI

29

55

53%

58

11

Ostertag

UTA

29

53

55%

58

12

Ming

HOU

28

42

67%

56

13

Gooden

ORL

28

56

50%

56

14

Baker

BOS

27

49

55%

54

15

Duncan

SAS

27

40

68%

54

16

Walker

DAL

26

54

48%

53

17

Foster

IND

26

48

54%

52

18

Marion

PHO

26

53

49%

52

19

Wilcox

LAC

25

39

64%

50

20

Gasol

MEM

25

55

45%

50

If you're not yet aware of what a force Zach Randolph is, then get aware! This guy is a bonafide superstar, probably the one player guaranteed to be on the Trailblazer roster next season, and one component of his spectacular all-round game is grabbing a teammate's missed shot and sticking in back in the basket.

The leaderboard is dominated by the big, powerful PF/C types. Some of the group could be said to have small offensive roles, and thus have lots of opportunity to get rebounds and subsequent layups. Dampier, Ostertag, Nesterovic might be placed in this class. Then you have a number of players who are strong scorers and still hit the offensive boards hard, sometimes getting putbacks from their own missed shots!

Players converting 60%+ of their follow-up attempts are guys other teams clearly need to be concerned about.

That's part one -- we'll return with the second half of this study in a few days.